When a catheter or probe is being placed in a human body, there is generally no aid in determining the path of the placement other than by intimate knowledge of the body part and by touch and feel or extraction of bodily fluid. An X-ray, sonogram or similar diagnostic device, however, is used to confirm the location of a catheter, for example, near the heart so as to rule out accidental placement into a lung, which often causes pneumothorax. The time required of such X-ray confirmation delays the use of such a central line catheter even in life threatening situations.